Billy had just completed his first trip for his new employers, Advanfort, and the ship was in international waters, heading to Egypt, when the Indian coastguard turned it back.

Ths ship was detained in Tuticorin in Tamil Nadu for two weeks before all the workers were arrested.

Yvonne, 25, said: “He should have been home now. All we want is to have him home for Christmas. He was on his way to Egypt to fly home.

He had texted me and was all excited to get home. Two days later, the company’s HR manager called me to say that Billy was in prison in India but that they would sort it out.

“The company have phoned me every day, twice a day, but they have no more information. Everyone on the ship was arrested.

“There is a boy of 17, an Estonian boy. He probably just cleans the ship and he is in prison too.

“They are being held on suspicion of committing offences under the Passport Act, Essential Commodities Act and the Firearms Act but they haven’t been charged.

“They are trying to say they had illegal firearms but the company gave documentation to say that everything was above board. Obviously I worry every time he goes away, but nothing bad has ever happened before.

“I realise Indian law has to run its course so it’s not their fault. It’s the British Government who are not helping these men out.”

Yvonne says the lack of information is very frustrating

Yvonne has had three letters from Billy via the British consulate. She said tearfully: “Billy is just saying that he sends his love to us all and that he doesn’t know anything.

“He says he is OK, but he would never tell me if he wasn’t. His mum and dad are in France and I am keeping in touch with them.”

Billy was born near Dumbarton and lived in Appin and Campbeltown, where he trained as a joiner, before going in to the Army at 20.

Argyll MP Allan Reid said: “I have been in touch several times with the Foreign Office, who assure me they have made representations to the Indian government.

“If the captain of the boat, or the owners, have committed any offence under Indian law it is not right to hold the men prisoner. They were merely passengers of the vessel.”